This invention relates to an image processing method and an image processing apparatus, and in particular, to an image processing method and an image processing apparatus suitable for use in an image printer.
In a conventional photographic print system, in order to obtain a well finished photographic print, it is actualized an image processing method in which an original to be printed is divided into a plurality of pixels beforehand for measuring light intensity, image data for evaluation is obtained, the characteristic values of the image are obtained, and a proper condition for printing is automatically obtained.
There are a variety of printing conditions such as, for example, xe2x80x98an average density valuexe2x80x99 for determining the duplicating conditions for images having a normal brightness distribution of photographic objects, xe2x80x98a density correction valuexe2x80x99 for making the correction of brightness in the case where the brightness distribution of photographic objects is deviated from a normal form, and xe2x80x98a color correction valuexe2x80x99 for correcting the color tone in the case where the average color balance is deviated from no color. The print exposure time and the exposure light intensity for a photographic paper have been determined on the basis of these print processing conditions to carry out the printing for duplicating an original.
On the other hand, it has been developed a digital photographic print system wherein image data are obtained by dividing an original into a plurality of pixels for measuring light by means of a scanner, a proper printing conditions are automatically obtained by the above-mentioned processing method, and on the basis of these, the aforesaid obtained image data are outputted to various kinds of image outputting apparatus after being subjected to a gradation conversion.
In order to obtain a proper printing conditions from the image characteristic values, it is often the case that mathematical equations such as a product and sum equation, a discriminant, and a conditional equation are used (hereinafter these are referred to as correction equations). The most suitable correction equation often varies depending on the magnitude and the character of the characteristic values to be obtained, and it is necessary that the equation is re-obtained in accordance with the kinds of means for obtaining the image data for evaluation, resulting in spending a large amount of time and labor.
Further, in a digital photographic print system, the quality of the image read by the scanner has greatly influenced the quality of the photographic print. In particular, if there is a large amount of flare component in the optical system for image reading of the scanner resulting from the inner surface reflection etc., taking an image from a negative-film for instance, the reproduced image is made to have an incomplete highlight portion and a poor modulation.
However, in the case where a smooth gradation expression, a high quality impression, and a stereoscopic impression are important, as in the case of depicting the face in the photography of a woman, for example, it is desirable that there is a certain measure of flare component; therefore, the real situation is that it does not exist an ideal optical system for reading an image that can read satisfactorily various kinds of images.
This invention has been made in consideration of the above-mentioned subject, and it is the first object of it to provide an image processing method and an image processing apparatus which can obtain a stable good photographic quality by adjusting the influence of the flare in the image reading system, and it is the second object of the invention to provide an image processing method and an image processing apparatus which can actualize a favorable photographic quality by making it possible to suitably adjust the flare quantity in the image reading system.
The above-mentioned objects of the invention can be accomplished by the following structures, methods and memory media memorizing the methods.
A) An image processing apparatus, comprises:
an optical system to for irradiating light to an image document, for detecting light transmitting through the image document or light reflected from the image document and for converting the light into electric signals, thereby obtaining a first image information, the optical system having an amount of flare;
flare amount memorizing means for memorizing an amount of flare of the optical system;
flare component calculating means for obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
determining means for determining on the basis of the flare component a copy condition on which the image document is copied.
B) An image processing apparatus, comprises:
an optical system for irradiating light to an image document, for detecting light transmitting through the image document or light reflected from the image document and for converting the light into electric signals, thereby obtaining a first image information, the optical system having an amount of flare;
flare amount memorizing means for memorizing the amount of flare of the optical system;
flare component calculating means for obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
image processing means for applying an image processing to the first image information on the basis of the flare component, thereby obtaining a second image information.
C) An image processing method, comprises steps of:
irradiating light to an image document, detecting light transmitting the image document or light reflected from the image document, converting the light into electric signals, and obtaining a first image information by an optical system;
obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
determining on the basis of the flare component a copy condition on which the image document is copied.
D) An image processing method, comprises steps of:
irradiating light to an image document, detecting light transmitting the image document or light reflected from the image document, converting the light into electric signals, and obtaining a first image information by an optical system;
obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
applying an image processing to the first image information on the basis of the flare component and obtaining a second image information.
E) A memory medium capable of memorizing a program capable of executing steps in such a manner that the program can be read from the memory medium by a computer, the steps comprises steps of:
irradiating light to an image document, detecting light transmitting the image document or light reflected from the image document, converting the light into electric signals, and obtaining a first image information by an optical system;
obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
determining on the basis of the flare component a copy condition on which the image document is copied.
F) A memory medium capable of memorizing a program capable of executing steps in such a manner that the program can be read from the memory medium by a computer, the steps comprises steps of:
irradiating light to an image document, detecting light transmitting the image document or light reflected from the image document, converting the light into electric signals, and obtaining a first image information by an optical system;
obtaining a flare component contained in the first image information on the basis of the first image information and the flare amount of the optical system; and
applying an image processing to the first image information on the basis of the flare component and obtaining a second image information.
The above-mentioned objects of the invention can be accomplished by any one of the methods and apparatus to be described in the following as preferable embodiments:
(1) An image processing method which measures light for each pixel, obtains image characteristic values on the basis of the data of said measured light, and determines the conditions for duplicating the original on the basis of said image characteristic values, wherein the flare quantity in the light measuring optical system carrying out said measurement of light is obtained, the flare component in said characteristic values is eliminated on the basis of said flare quantity, and the conditions for duplicating the original are determined.
According to this method, correct image characteristic values can be obtained by eliminating the influence of the flare completely, and an image of stable quality can be obtained.
(2) An image processing method which divides an image of an original into a plurality of pixels for measuring light, obtains image characteristic values on the basis of the data of said measured light, and determines the conditions for duplicating the original on the basis of said image characteristic values, wherein the flare quantity in the light measuring optical system of the image processing apparatus is obtained, and the flare component in said image characteristic values is converted into a flare quantity equivalent to a predetermined standard flare quantity from the difference between the above-obtained flare quantity and said standard flare quantity.
According to this method, an image quality optimized by a standard unit can be obtained simply, by modifying the image characteristic values from the difference between the predetermined standard flare quantity and the measured flare quantity and determining the conditions for duplicating the original.
(3) An image processing method which measures light for each pixel, and makes image output after executing a predetermined gradation conversion processing, wherein the flare quantity in the light measuring optical system carrying out said measurement of light is obtained and a gradation correcting process for correcting said flare is made.
According to this method, an image having a high modulation influenced by no flare component can be obtained by executing the gradation correcting process making the flare zero on the basis of the flare quantity in the light measuring optical system.
(4) An image processing method which measures light for each pixel, and makes image output after executing a predetermined gradation conversion processing, wherein the flare quantity in the light measuring optical system carrying out said measurement of light is obtained, and said image is converted into an image having a flare quantity equivalent to the predetermined standard value.
According to this method, an image quality having a smooth gradation and a high modulation can be obtained by making a flare correction for an arbitrary flare quantity on the basis of the flare quantity of the light measuring optical system and the predetermined standard value.
(5) An image processing method set forth in the paragraph (2) or (4), wherein the aforesaid standard flare quantity is determined to be a value varying in accordance with the kinds of original images.
According to this method, an optimum standard flare quantity can be determined for the originals having different characteristic values such as a negative-film and a positive-film (a slide-film); hence, a more favorable image quality can be obtained.
(6) An image processing method set forth in any one of the foregoing paragraphs, wherein the aforesaid flare quantity is calculated in such a way as described below:
a first image is obtained by reading a first original having two areas, that is, a central portion which is an area equal to or smaller than one forth of the whole original area and a peripheral portion which is an area except said central portion, by means of the aforesaid light measuring optical system, and a second image is obtained by reading a second original which has a density lower than said first original only in said peripheral portion by 1.0 to 2.5 by means of said light measuring optical system; then the flare quantity F1 is calculated by the following equation:
F1=(PCxe2x88x92PA)/PB,
where PA is the average of the measured light values in the central area of the first image, PB is the average of the measured light values in the whole area of the second image, and PC is the average of the measured light values in the central area of the second image.
According to this method, a measurement of a flare quantity having a sufficiently high brightness can be simply and quickly done without making a remarkable alteration to the image reading system.
(7) An image processing apparatus comprising an image inputting means for obtaining an original image data by measuring light for each pixel, a flare quantity correcting means for converting said original image data into a flare-corrected image on the basis of the flare quantity in said image inputting means and a predetermined standard flare quantity, an image processing means for obtaining image characteristic values of the original and determining the conditions for duplicating the image from said image characteristic values, and an image recording means for recording said flare-corrected image on an image recording medium on the basis of said conditions for duplicating.
According to this structure, the flare quantity of the image inputting means contained in the read image can be adjusted to a predetermined quantity; hence, a print quality suitable for the purpose can be obtained.
(8) An image processing apparatus set forth in the paragraph (7) further comprising a standard value memorizing means for memorizing a plurality of standard flare quantities, wherein the aforesaid flare quantity correcting means has a function to select out one standard flare quantity from said standard value memorizing means.
According to this structure, an optimum standard flare quantity can be determined for the originals having different characteristics such as a negative-film and a positive-film (a slide-film), or an image of a person and an image of a landscape; hence, a more favorable image quality can be obtained.